<!DOCTYPE html>
<title>position:sticky should operate correctly for the root scroller</title>
<link rel="help" href="https://drafts.csswg.org/css-position-3/#valdef-position-sticky">
<link rel="help" href="https://drafts.csswg.org/cssom-view/#propdef-scroll-behavior">

<style>
    body {
        /* Assumption: 3000px is taller than any user agents test window size. */
        height: 3000px;
        /* A property which propagates for <html>. */
        overflow-x: hidden;
    }

    #sticky {
        position: sticky;
        top: 50px;
        width: 200px;
        height: 200px;
        background-color: green;
    }
</style>

<div id="sticky">This is a sticky element!</div>

<script>
    let sticky = document.getElementById('sticky');
    window.scrollTo(0, 700);
    assert_equals(sticky.offsetTop, 700 + 50);
</script>